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Commit d57de5a3 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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[S390] Use diag260 for memory size detection. 



Avoid the tprot loop if diag260 works and reports that there are no
holes in memory. The tprot instruction can lead to a significant delay
in the ipl process if the virtual guest has a lot of memory and the
host is under memory pressure.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 29b08d2b

arch/s390/kernel/head64.S

+15 −2
Original line number Diff line number Diff line
@@ -70,7 +70,22 @@ startup_continue: 
	sgr	%r5,%r5 		# set src,length and pad to zero

	mvcle	%r2,%r4,0		# clear mem

	jo	.-4			# branch back, if not finish

					# set program check new psw mask

	mvc	__LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)

	larl	%r1,.Lslowmemdetect	# set program check address

	stg	%r1,__LC_PGM_NEW_PSW+8

	lghi	%r1,0xc

	diag	%r0,%r1,0x260		# get memory size of virtual machine

	cgr	%r0,%r1			# different? -> old detection routine

	jne	.Lslowmemdetect

	aghi	%r1,1			# size is one more than end

	larl	%r2,memory_chunk

	stg	%r1,8(%r2)		# store size of chunk

	larl	%r2,memory_size

	stg	%r1,0(%r2)		# set memory size

	j	.Ldonemem



.Lslowmemdetect:

	l	%r2,.Lrcp-.LPG1(%r13)	# Read SCP forced command word

.Lservicecall:

	stosm	.Lpmask-.LPG1(%r13),0x01	# authorize ext interrupts
@@ -139,8 +154,6 @@ startup_continue: 
	.int	0x100000



.Lfchunk:

					# set program check new psw mask

	mvc	__LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)



#

# find memory chunks.